using System;

using System.Collections.Generic;   

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine( dup.calc( new int[] {1, 2, 3, 4, 2 }) )  ;

        Console.WriteLine( redu.calc( new int[] {1, 1, 5, 2 }) );       

    }

    public static class redu

    {

        public static int Sum(int Item , int Tally )

        {

            return Item + Tally;

        }

​

        public static int calc (int[] ary)

        {              

            Func< int,int, int> add = Sum;  

            int output = ary.Aggregate(add);

            return output;

        }

    }

​

    public static class dup

    {

        public static bool calc (int[] ary) {

            bool output = false;

            Dictionary <int ,int> found = new Dictionary<int,int>();        

​

            foreach (int i in ary ){

                if(found.ContainsKey(i)){

                    found[i] ++;

                    output = true;

                    break;

                }else{

                    found.Add(i,1);

                }

            }   

            return output;

        }

    }

}

​

​